View Full Version : AR15 or M16 parts

March 25, 2002, 02:43 PM
This should be a simple question for the well full of knowledge in this group.

My friend's father just passed away and he had few AR types with all kinds of spare parts. Well my friend not being the sportsman like me sold the guns then found the parts a few days later and being the friend he is gave them to me. I jumble of parts being springs, hammers, disconnectors, and selectors just to name a few and some of the Zip-loc bags say M16 on them.........Finally to the question are there any differences in M16 to AR15 parts ( besides the missing auto- disconnector)? I have a Bushmaster shorty will the M16 parts fit or are there any other factors that I should be aware about?


March 25, 2002, 02:53 PM
The bolt carrier is different in a 16. The AR15 carrier is hollowed out closer to the end to preclude it being used in a M16. Example, put a AR15 carrier in a 16 and nothing happens on full auto because the auto sear is not engaged by the carrier. Also, the "BATmen" have decided through devine inference that ONE M16 part in an AR15 constitutes a "machine gun" and you can be prosecuted for same......... The trigger, disconnector, sear, and carrier are the only parts that are different between the two rifles.
Everything else is interchangeable without legal problems.


I forgot the safety/selector switch is also included in the above list.

March 25, 2002, 03:10 PM
Almost all of the fire control parts are different, except pins and springs. An M16 hammer has different geometry from most AR hammers (and there are several types of those), M16 firing pins are of different dimensions, as are the bolt carriers. The disconnector, sear and trigger can also be different, even from one AR model to another. You can easily convert the M16 parts if you want. Most M16 parts simply have an additional extension of steel that differentiates their function from the corresponding AR part.

March 25, 2002, 03:14 PM
This link AR-15 Semi-Auto vs. Full-Auto parts (http://www.ar15.com/articles/article.html?article=31), will provide you with what you need to know, and hopefully keep you from running afoul of the law.

March 26, 2002, 12:44 AM
Thanks guys I app. your guidence